by Tom Vanden Brook, USA TODAY

by Tom Vanden Brook, USA TODAY

WASHINGTON -- Defense Department employees will know 30 days in advance of any unpaid furloughs they may face as part of the impending spending cuts scheduled to take effect March 1, Defense Secretary Leon Panetta said in a message to all employees Wednesday.

"Today, I notified Congress that furloughs could occur under sequestration," Panetta said. "I can assure you that, if we have to implement furloughs, all affected employees will be provided at least 30 days' notice prior to executing a furlough and your benefits will be protected to the maximum extent possible."

The furloughs are required as part of the mandatory spending cuts set to kick in March 1 across virtually all parts of the federal government unless Congress and President Obama agree to a plan to avoid them. All told, $1.2 trillion in spending cuts are set to occur over the next 10 years as part of a deal reached in the summer of 2011 between Obama and Congress to avoid defaulting on federal debt obligations.

Furloughs will not begin for the Pentagon's civilian employees until late April because of required notifications to Congress and the workers, said Robert Hale, the Pentagon's comptroller. He estimated 750,000 Pentagon employees would be affected by mandatory unpaid leave, and that the Pentagon would save $4 to $5 billion in wages.

The Pentagon's budget crunch stems from sequestration and operating under a 2012 spending plan because Congress hasn't approved a 2013 budget. The result of working under the 2012 budget, Hale said, is that Pentagon today is spending more on weapons programs than its operations and maintenance accounts. In addition, costs have also been higher than anticipated in Afghanistan because transportation costs have risen, and fighting has been more intense than anticipated.

Some employees will be exempt from furloughs if their jobs are directly related to providing health care or public safety, Hale said.

Jessica Wright, the acting under secretary of Defense for personnel, said the furloughs would have a "catastrophic" effect on civilian employees and their families.

Overall, the military faces $500 billion in budget cuts over 10 years from the cuts, which are known as sequestration.

Panetta said he and Obama are working to stave off the $46 billion in spending cuts by the end of this fiscal year on Sept. 30 for all the services to meet the requirement for 2013.

"For more than a year and a half, the president, the Joint Chiefs of Staff and I have repeatedly voiced our deep concerns over the half a trillion dollars in automatic across-the-board cuts that would be imposed under sequestration and the severe damage that would do both to this department and to our national defense," Panetta said.

Documents obtained Tuesday by USA TODAY show that the services' spending cuts scheduled to take effect March 1 will force almost $34 billion in wage and spending reductions.